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The flatworm mitochondrial genome: an expansion into the phylogeny and molecular epidemiology of taeniid tapeworms

扁虫线粒体基因组：绦虫系统发育和分子流行病学的扩展

基本信息

批准号：
12670228
负责人：
NAKAO Minoru
金额：
$ 2.18万
依托单位：
Asahikawa Medical College
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12670228/
关键词：
Mitochondria Genome Platyhelminthes Cestode

项目摘要

The mitochondrial genetic code of cestodes was presumed. In the Platyhelminthes the codon UAA was assigned as tyrosine; however, it became clear that it is the termination codon like other metazoan animals. Moreover, we defined that the codon GUG serves as an initiation codon.The complete DNA sequences of the mitochondrial genomes (mtDNA) of the tapeworm Echinococcus multilocularis and Taenia solium have been determined. The E, multilocularis mtDNA is a circular genome (13,738 bp in length) and contains 36 genes (12 for proteins involved in oxidative phosphorylation, 2 for rRNAs and 22 for tRNAs) but a gene for ATP8 is missing. All genes are transcribed in the same direction. The gene arrangement is characteristic but the partial organization between ND1 and Cox1 genes is similar to those of annelid mtDNAs, suggesting that the Platyhelminthes is derived within the Eutrochozoa. The T. solium mtDNA is 13,709 bp in length and its gene arrangement is identical with that of the E. multilocularis mtDNA. In a gene for ND1, the abbreviated stop codon U was confirmed for the first time in flatworm mtDNAs. A sequence analysis of CDNA demonstrated that the complete termination codon UAA is created post-transcriptionally by polyadenylation.Genetic polymorphism was determined among geographic samples of T. solium, using PCR-amplified sequences of Coxl and Cytb genes. The Asian samples from China, Thailand, Irian Jaya, and India formed a single cluster; however, the Latin American samples from Mexico, Peru, Ecuador, Bolivia, and Brazil combined with the African samples from Tanzania, Mozambique, and Cameroon to form an additional cluster. These results and historical data of swine domestication suggest that T. solium was introduced recently into Latin America and Africa from different parts of Europe and that the tapeworm of another origin was independently spread in Asian countries.

推测了绦虫的线粒体遗传密码。在扁形动物中，密码子 UAA 被指定为酪氨酸；然而，很明显它是像其他后生动物一样的终止密码子。此外，我们定义密码子GUG作为起始密码子。多房棘球绦虫和猪带绦虫的线粒体基因组（mtDNA）的完整DNA序列已经确定。 E, multilularis mtDNA 是一个环状基因组（长度为 13,738 bp），包含 36 个基因（12 个涉及氧化磷酸化的蛋白质、2 个 rRNA 和 22 个 tRNA），但缺少 ATP8 基因。所有基因都以相同方向转录。基因排列具有特征性，但 ND1 和 Cox1 基因之间的部分组织与环节动物 mtDNA 相似，表明扁形动物起源于真轮动物门。 T. solium mtDNA 长度为 13,709 bp，其基因排列与 E. multilularis mtDNA 相同。在 ND1 基因中，缩写的终止密码子 U 首次在扁虫 mtDNA 中得到证实。 CDNA 序列分析表明，完整的终止密码子 UAA 是通过多聚腺苷酸化在转录后产生的。使用 PCR 扩增的 Coxl 和 Cytb 基因序列，确定了 T. solium 地理样品中的遗传多态性。来自中国、泰国、伊里安查亚和印度的亚洲样本形成一个簇；然而，来自墨西哥、秘鲁、厄瓜多尔、玻利维亚和巴西的拉丁美洲样本与来自坦桑尼亚、莫桑比克和喀麦隆的非洲样本结合起来形成了一个额外的簇。这些结果和猪驯化的历史数据表明，猪绦虫最近从欧洲不同地区引入拉丁美洲和非洲，而另一个起源的绦虫则在亚洲国家独立传播。